Wednesday, October 31, 2012

What would happen if humans evolved to fill all the ecological niches? Perhaps something like the creepy landscape envisioned by film maker Brian Andrews, who placed human skeletons inside a variety of animal forms. For your Halloween viewing pleasure:You can see more by Andrews on his website.Hat tip: Not Exactly Rocket Science.

Tuesday, October 30, 2012

As you know, our galaxy is called the Milky Way. Although
we know far more about it than about other galaxies, it has been difficult to
catalogue all the stars contained within it, particularly those located in the
galactic center. The stars in this region are packed tightly together into a
distended bulge that is obscured by dust. Luckily, infrared telescopes can see
through that dust. Enter the VISTA telescope and
a team of cosmologists led by Roberto Saito of Pontificia Universidad
Catolica de Chile, Universidad de Valparaiso and The Milky Way Millennium
Nucleus, Chile.

Between 2010 and 2011, the VISTA telescope was used to
observe the Milky Way bulge in five different passbands (ranges of wavelengths).
This data was compiled to make up the Variables in the Via Lactea
(VVV), a public survey of the Milky Way. Saito and his colleagues used the VVV to create the following
stunning panorama:

Caption: This striking view of the central parts of the
Milky Way was obtained with the VISTA survey telescope at ESO’s Paranal
Observatory in Chile. This huge picture is 108,500 by 81,500 pixels and contains
nearly nine billion pixels. It was created by combining thousands of individual
images from VISTA, taken through three different infrared filters, into a
single monumental mosaic. These data form part of the VVV public survey and
have been used to study a much larger number of individual stars in the central
parts of the Milky Way than ever before. Because VISTA has a camera sensitive
to infrared light it can see through much of the dust blocking the view for
optical telescopes, although many more opaque dust filaments still show up well
in this picture.

Credit: ESO/VVV Consortium Acknowledgement: Ignacio Toledo.

Okay, so it’s not that stunning, as astronomy pictures go. But keep in mind that this is
the first single diagram of the entire Milky Way bulge, and that it contains
over 84 million stars. Saito, R., Minniti, D., Dias, B., Hempel, M., Rejkuba, M., Alonso-García, J., Barbuy, B., Catelan, M., Emerson, J., Gonzalez, O., Lucas, P., & Zoccali, M. (2012). Milky Way demographics with the VVV survey Astronomy & Astrophysics, 544 DOI: 10.1051/0004-6361/201219448

Monday, October 29, 2012

Here’s a result that should surprise no one. High-risk
children who are adopted out of foster care by gay or lesbian couples fair just
as well as kids adopted by heterosexual couples. This seems so obvious I
shouldn’t have to explain the data, but of course, that’s not how science
works. So, here it is:

Eighty-two children under age nine who underwent public
adoptions in Los Angeles County were examined at two, twelve and twenty-four
months post-adoption. Behavior and cognitive ability was assessed at each time
point. The kids were also evaluated for differences in their background that
could affect behavior or intelligence, such as prior neglect or prenatal substance
exposure.

As expected, the kids from the gay households did not differ
in any meaningful way from kids in straight households. This was true despite
the fact that the children adopted by gay or lesbian couples often had significantly greater background risk factors. All the children benefited
equally from adoption, as shown by an average gain of about 10 IQ points after
leaving foster care. These data corroborate prior studies demonstrating that children
raised by gay or lesbian parents are indistinguishable from those raised by
heterosexual parents in attitude, behavior or gender-role development.

In the
U.S., over a hundred thousand kids are currently awaiting adoption. Many of
these kids have physical or mental health issues, often stemming from whatever
landed them in foster care in the first place. Adoption can often mitigate
these problems. By all means, let’s widen the pool of potential parents as much
as possible. Lavner, J., Waterman, J., & Peplau, L. (2012). Can Gay and Lesbian Parents Promote Healthy Development in High-Risk Children Adopted From Foster Care? American Journal of Orthopsychiatry, 82 (4), 465-472 DOI: 10.1111/j.1939-0025.2012.01176.x

Friday, October 26, 2012

Just when you thought prions couldn’t get any scarier, you
find out that some birds can pass the infectious proteins intact through their
digestive systems. Yes, crows can pick up prions from eating infected meat, and
then pass those prions on in their feces. This cheery news is courtesy of Kurt
VerCauteren and his colleagues at the United States Department of Agriculture.

Prions are infectious misfolded proteins. Normally, malfunctioning
proteins are simply discarded or dismantled, but not so with prions. Upon
introduction into a cell, these peptides induce other proteins to misfold as
well. In other words, prions are communicable despite having no genetic material.
This rampant misfolding results in a number of incurable, deadly neurological
diseases known as transmissible spongiform encephalopathies (TSEs). An example
would be bovine spongiform encephalopathy, a.k.a. mad cow disease.

Wild animals also succumb to prions and are often scavenged
by crows. To test whether prions can be spread by foraging crows, the
researchers fed some captured wild American crows the brains of mice infected
with prions. The crows’ feces were collected, radiated to kill microbes,
diluted, and injected back into mice. 100% of the unfortunate mice treated in
this manner came down with TSE. If this doesn’t sound ominous, let me remind
you that crows can travel far distances and are indiscriminate poopers.

On the
plus side, if you’re not in the habit of ingesting fecal material, you probably
don’t have an increased risk of contracting TSE yourself. On the other hand,
these data do suggest that it would be nearly impossible to keep prions
contained. Short of clearing up every infected carcass before crows or other
avian scavengers can get to them, there’s not much we can do.

Thursday, October 25, 2012

Regardless of one’s feelings about the second amendment,
most people agree that it’s important to keep children safe from firearms. The
American Academy of Pediatrics (AAP) fully endorses this view. The data clearly show
that the safest home for children is one without guns. According to the Centers
for Disease Control and Prevention, in 2010, gun violence was the fourth most
common cause of injury death among children ages five to fourteen and the
second most common cause of injury death in older children. These deaths were
divided between homicides and suicides.

No one believes that the 38% of households that currently
contain guns will give them up. In lieu of that, there are some sensible
measures that could go a long way to protecting children and adolescents from
gun violence.

Child
access prevention laws that enforce safe storage practices including the
use of trigger locks, lock boxes, and gun safes.

Regulation
of the purchase of guns, including mandatory waiting periods, closure of
the gun show loophole, mental health restrictions for gun purchases, and
background checks.

Restoration
of the ban on the sale of assault weapons to the general public.

I
strongly favor each of these measures.Council on Injury, Violence, and Poison Prevention Executive Committee (2012). Firearm-Related Injuries Affecting the Pediatric Population PEDIATRICS DOI: 10.1542/peds.2012-2481

Tuesday, October 23, 2012

You may have heard that dolphins sleep with only half of
their brains at a time. Like me, you may have assumed that, while the awake
hemisphere was capable of preventing the animals from drowning, it wasn’t completely alert. Not so. Apparently, dolphins can respond to echolocation and training
cues with full concentration indefinitely. Or at least, for the fifteen straight days demonstrated by this study.

Researchers from marine mammal programs in San Diego, led
by Brian Branstetter of the National Marine Mammal Foundation, asked two
dolphins (SAY and NAY) to search their water enclosure for simulated
echolocation targets. Upon detecting a target, the dolphins could press a
response paddle and receive a reward. After training, the dolphins each
participated in two 5-day sessions of round-the-clock target simulation. Both
of the dolphins maintained a correct response rate of over 75%, but because SAY
did a little better (she was correct 95% of the time), she got the honor of
participating in a 15-day test. That test was actually supposed to last thirty
days, but was cut short by a storm. SAY’s performance remained strong
throughout this longer interval.

SAY

Credit: Brian Branstetter

During unihemispheric sleep when only half their brains
are awake, dolphins are not merely maintaining breathing and other bodily
functions. They can respond to their surroundings with full alertness. If you
consider that many dolphin populations are at constant risk of attack from
sharks, perpetual vigilance sounds like a great idea.

Monday, October 22, 2012

Catherine Price and Peter
Banks from the universities of New South Wales and Sydney may have found a way
to protect endangered native species from predators. It seems that predators
are less likely to find and kill prey if the hunters have been pre-exposed to
the scent of that prey. At least, that was the case for black rats hunting
quails’ eggs.

The experiments were conducted
in one-hectare square grids in shrubby areas known to contain large black rat
populations. These rats were more than happy to raid birds’ nests for eggs or
nestlings, though they had not previously encountered quail. The researchers
introduced the scent of quail nests (more specifically, feathers and feces) to
the test areas. In some cases, the scent was spread around for seven days after which artificial nests containing actual quail eggs were introduced. In
other tests, the scent and the nests were imported into the rats’ territories
at the same time.

In regions where the quail
smells were introduced a week prior to the nests, quails’ eggs had a 62%
greater survival rate. In other words, after prolonged exposure to quail smells that were not associated with nests, the rats ceased hunting for quail eggs. In
essence, the rats were being taught to ignore quail nest smells.

How
would this help in a real world setting? While ecologists probably can’t
continuously pipe prey smells throughout natural parks, they might be able to
do so for a few days prior to a planned reintroduction of an endangered
species. This might give a vulnerable species a head start on reestablishing itself
in the region.Price, C., & Banks, P. (2012). Exploiting olfactory learning in alien rats to protect birds' eggs Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1210981109

Friday, October 19, 2012

You’ve probably heard about the ‘marshmallow test’ for
impulse control. Briefly, young children are given one marshmallow and told
that if they can delay eating it for a few minutes, they’ll get a second marshmallow.

The original experiment was conducted in the 60’s at Stanford University, but cognitive scientists and parents have been repeating the experiment ever since. Here's an example you might enjoy.

Why such interest in whether kids can resist a marshmallow? When those children were revisited later in
life, the ones who had been able to delay gratification at age four seemed to have some huge advantages. For example, they had higher SAT scores and suffered from
less substance abuse. Apparently, being able to postpone eating a tasty treat
as a preschooler has implications for one’s success in life. Or does it? Not so fast.

Celeste Kidd, Holly Palmeri and Richard Aslin of the
University of Rochester repeated the marshmallow test, but with a twist. This
time, prior to giving children their first marshmallow, they set up scenarios
where a facilitator was seen as either ‘reliable’ or ‘unreliable’. Children
were offered a handful of crayons or stickers for a project and told that if
they could wait, the staffer would go and fetch a much better collection of
materials. For one group of kids, the adult did indeed return with some particularly enticing supplies
(reliable).For the second group of
children, the adult came back empty handed (unreliable), explaining that there
weren’t any more materials after all. After two experiences with the adult
being either reliable or unreliable, the kids were presented with their
marshmallows and the real test began.

The kids who had been paired with a reliable facilitator
were able to wait an average of four times longer than the children who had
been twice disappointed by an unreliable adult. This difference may have been
underestimated by the fact that each test was terminated after 15 minutes, by
which point only one out of fourteen children in the unreliable group but nine
out fourteen in the reliable group still had their marshmallow. In other words,
many of the kids in the reliable group might have been willing to wait far
longer.

While young children clearly have difficulty with impulse
control, this study contradicts the view that differences in that control are
purely innate. Instead, the data suggest that the majority of young children
use a rational process to decide whether or not to wait for a reward. After
all, if you can’t trust someone to bring you a second marshmallow, you might as
well go ahead and eat the one in front of you.

Thursday, October 18, 2012

The 2012 Nobel prizes were
announced last week. Here are the winners in physics, chemistry and medicine,
complete with video explanations.

Serge Haroche and David Wineland
won the physics prize "for ground-breaking experimental methods that
enable measuring and manipulation of individual quantum systems". In essence, they showed that, contrary to
conventional wisdom, it is
possible to observe and measure a single photon of light.

The chemistry award went to Robert Lefkowitz and Brian
Kobilka “for studies of G-protein-coupled receptors".Receptors are protein complexes that span cell membranes. Most drugs
work by binding to particular membrane receptors.

The prize for medicine went to Sir John Gurdon and Shinya
Yamanaka “for the discovery that mature cells can be reprogrammed to become
pluripotent". Normally, when mature cells
divide, they can only give rise to more of the same kind of cell. Thanks to the
breakthroughs celebrated by this award, researchers can now induce some mature
cells to forget their programming and give rise to any kind of cell.

The award ceremony will take place in Stockholm, Sweden on
December 10th.

Wednesday, October 17, 2012

On Sunday, Felix Baumgartner performed a record breaking space jump. He jumped from the greatest height ever and was the first to break the sound barrier in free fall. He was carried to a height of 39 km in a capsule suspended from a gigantic helium balloon. He free-fell for over four minutes, reaching a top speed of 1,342.8 km/hour (mach 1.24, or 1.24 times the speed of sound) before his parachute successfully deployed. He even stuck the landing.Not to say that there weren't some tense minutes. As you can see in the video, he tumbled head over heels for a while before gaining control.

Tuesday, October 16, 2012

Researchers led by Sukhbinder Kumar of Newcastle University
have been studying this burning question: why do some sounds make us flinch?
We’re not talking about sounds that are so loud that they hurt our ears, but
rather sounds we can’t stand even at what would otherwise be comfortable
volumes. It turns out that these sounds create a feedback loop between the
auditory cortex, which processes sounds, and the amygdala, which is involved in
emotion and memory.

Thirteen healthy volunteers were asked to listen to 74
distinct sounds, many of which had been previously judged to be highly disagreeable, while
undergoing MRI scans. The subjects rated each sound from 1 (least unpleasant)
to 5 (most grating). Activity in both the auditory complex and the amygdala
were linked with the unpleasant sounds. The authors believe that the stimulus
travels from the auditory complex to the amygdala, where it is given an
emotional tag, and then back to the auditory complex. This cycle can be
repeated many times, increasing the degree of aversion to the sound.

Monday, October 15, 2012

There are thousands of genetic
diseases, many of which are lethal in untreated newborn babies. Unfortunately,
the conventional whole genome sequencing (WGS) methods required to detect these
defects can take up to six weeks—time that infants may not have. Thanks to the efforts
of more than twenty authors (and countless other people) from Children’s Mercy
Hospital and two universities in Kansas City, MO, WGS can now be done in just
over two days.

Several innovations were
responsible for this great decrease in time. First, sample preparation time was
decreased from sixteen hours to only 4.5 hours. The sequencing itself, which
used to take well over a week, was reduced to just over one day. Finally, the
subsequent analysis time was likewise drastically reduced. By combining these
time saving factors, the researchers were able to successfully complete WGS on
several infants in only fifty hours. Because much of the work was fully
automated, only five of those hours required human involvement.

Although many genetic diseases can be managed with prompt and proper
care, there are sadly many others for which any treatment is futile. However,
even in cases where an infant has an inevitably fatal illness, parents may
still benefit from knowing sooner rather than later. In some cases, rapid WGS
might quickly rule out suspected genetic diseases, or help researchers find
genetic connections for diseases with unknown causes. For these reasons, this new technique will probably find wide use in hospitals.Carol Jean Saunders, & et al (2012). Rapid Whole-Genome Sequencing for Genetic Disease Diagnosis in Neonatal Intensive Care Units Science Translational Medicine DOI: 10.1126/scitranslmed.3004041

Friday, October 12, 2012

Some species of ants will raid the nests of rival ants, kill
or drive off the adults and carry the babies back to their own nests. Once
imprisoned in the conquerors’ nest, the baby ants are put to work caring for
their new ruling class. Enslaving ants in this way is a form of ‘brood
parasitism’. You may be more familiar with this term as it relates to cuckoos
laying their eggs in other birds’ nests. Just as the host birds rear young that
is not their own, so too must the enslaved host ants rear unrelated parasitic
ants.

Slave-making ants are well equipped for warfare with their
fellow ants, but not so well prepared to care for themselves. In some cases,
their nests are entirely dependent on the foraging and caretaking abilities of
their enslaved conquests. To some degree, this puts them at the mercy of their
slaves. According to Tobias Pamminger and his colleagues from the Gutenberg
University of Mainz and the Ludwig Maximilian University of Munich, the slaves
can rebel by refusing to care for their ‘masters’.

In fact, the researchers found that only half as many pupae
in the slave makers’ nests survive as pupae in undisturbed host nests. In
other words, host workers make perfectly capable nurses when it suits them, but
make little effort to rear the parasitic offspring of their slavers. They may
neglect those young or even actively slaughter them.

What’s interesting about this is that the enslaved workers
can gain no direct benefit from their ‘slave rebellion’. They can never escape
and they can never reproduce. On the other hand, their fellow hosts do benefit if
the slaver nest is weakened. By decreasing the number of parasitic slave
makers, the enslaved hosts could be protecting other members of their species
from the same fate. Apparently, this form of ‘kin selection’ is enough to make the slave rebellion trait a widespread phenomenon.

Thursday, October 11, 2012

About ten percent of women
experience some sort of hypertensive disorder, such as pre-eclampsia, while pregnant. Unfortunately,
according to fourteen Finnish scientists, led by Soile Tuovinen of the
University of Helsinki, high blood pressure during pregnancy is associated with
lower cognitive ability in the resulting boy babies. I’m sure that knowing this
will in no way affect the blood pressure of expecting mothers.

The researchers used data from the
Helsinki Birth Cohort Study. About 900 men who were born between 1934 and 1935
had undergone cognitive ability tests when they were twenty (prior to
compulsory military service). Boys whose mothers had had high blood pressure
while they were pregnant had slightly lower cognitive scores than boys whose
mothers had had normal pregnancies. When retested at age 68, men from normal
pregnancies showed no change in cognitive ability, but men from hypertensive
pregnancies showed a slight decline in cognitive ability. By the way, this isn’t
to suggest that women are not similarly affected. They just weren’t part of
this study.

Even if this connection between hypertension and IQ does hold true, I don’t think it warrants any extra treatment or paranoia. For one thing, because hypertensive disorders are potentially
very dangerous to the mother, pregnant women should already be having regular prenatal
screenings to detect and treat any such conditions. For another, the differences in cognitive ability were not great. But as
ever, check with your doctor if you have any concerns. Soile Tuovinen, Katri Raikkonen, Eero Kajantie, Markus Henriksson, & et al. (2012). Hypertensive disorders in pregnancy and cognitive decline in the offspring up to old age Neurology DOI: 10.1212/WNL.0b013e31826e2606

Wednesday, October 10, 2012

When I heard that 3D display screens were coming to tablet computers, I wasn't expecting this. I'm not sure this is ready for prime time yet, but judge for yourself:The 'Tilt Display' shown above was developed by researchers at the University of Bristol.

Tuesday, October 9, 2012

Ever wish you could split a drop of water cleanly in two? Well, thanks to the advances of Ryan Yanashima and his colleagues from Arizona State University, that dream may now be a reality.Ordinarily, if you try to cut a water droplet precisely in
half, the original drop shatters into multiple, and often unusable, droplets.
However, if you make your knife ‘superhydrophobic’, meaning that water can’t
stand to touch it, the droplet will slice cleanly in two. To create these
water-hating knives, the researchers began with polyethylene knives and then
attached hydrophobic solvents in a several step procedure. You can see the
result below.

This just leaves one question: why would you need to chop a
water drop in half? There are actually a lot of
medical and industrial uses. The important difference between this method and
shattering a drop is that by slicing the droplet in half you don’t lose any
volume. Remember, anything in the droplet (dissolved medicines, solvents,
proteins, etc) will also be divided. Not only the water, but also your valuable ingredients are lost in the satellite droplets you create by
fragmenting a drop of your favorite solution. In contrast, you save every bit of material by slicing your water.

Monday, October 8, 2012

Humans were already eating meat on a regular basis one and a half million years ago. You may be surprised to learn how an international team of paleontologists reached this conclusion. It wasn’t just physical evidence in the form of butchery marks on bones, though we do have such clues. No, it was a case of 1.5 million year old malnutrition.

The scientists found the ancients skull fragments of a two-year child suffering from porotic hyperostosis. This disease is often associated with iron-deficiency anemia. In very young children, it is often caused by a vitamin B12 deficiency, either in their mother’s milk or in their own post-weaning diets.

Vitamin B12 is one of the few nutrients that people on strict vegetarian diets (no animal products of any kind) usually need to supplement. This is because it’s not found in plant sources, unless those sources have been artificially fortified. The fact that this unfortunate child likely died of what’s essentially a meat deficiency strongly suggests that meat was a routine and critical part of his community’s diet.

A fragment of a child's skull discovered at Olduvai Gorge, Tanzania, shows the oldest known evidence of anemia caused by a nutritional deficiency.

Friday, October 5, 2012

When something suddenly appears in our visual field, we
usually notice right away. That isn’t the case when something changes or
disappears. Even though the difference is equivalent, it takes us a lot longer
to register the loss or alteration of an object within our field of view. This
phenomenon has been termed ‘change blindness’. You can see an example here.

Apparently, the same is true for our sense of hearing.
University College London researchers led by Francisco Cervantes Constantino
tested people for ‘change deafness’. They played specific sets of 4 to 14 pure
tones for groups of people with normal hearing. Each auditory scene lasted from
two to four seconds. In some trials, a tone was either added or subtracted
partway through the sound-scape. You can see a visual representation of these
trials below.

Participants did significantly
better at detecting when a tone was added than when one was subtracted. As more
tones were added to the original mix, people became worse and worse at noticing
the disappearance of one sound. In contrast, the subjects were close to 100%
accurate in detecting the addition of a new tone even when listening to
fourteen other notes. People were also far more adept at identifying exactly which
tone had been added than which had been removed.

It’s not surprising that we’re attuned to pick up the commencement of
new sounds in our environment. After all, a sudden sound may augur the arrival
of a predator or other danger. However, it is interesting that we’re much less
likely to notice the cessation of sounds. Anyone with a young child can tell
you why this can be problematic. Francisco Cervantes Constantino, Leyla Pinggera, Supathum Paranamana, Makio Kashino, & Maria Chait (2012). Detection of Appearing and Disappearing Objects in Complex Acoustic Scenes PLoS ONE : doi:10.1371/journal.pone.0046167

Thursday, October 4, 2012

By now, everyone has heard of the catastrophic losses to
honeybee populations due to a phenomenon known as ‘colony collapse disorder’.
While environmental factors such as pollution and pesticides have been
implicated, one of the leading causes is probably infection by a parasitic mite
named Varroa destructor.

Luckily, bees have evolved
some mechanisms for mitigating V. destructor infestations. One such method is called hygienic
behavior (HB). In essence, it involves uncorking infected larvae from their
sealed brood cells and chucking the sick babies out of the hive. However, not
all bees or colonies of bees display the same degree of HB. If apiarists could
breed for greater hygiene activity, they might be able to protect their bees
from colony collapse.

The first step in creating a
resistant bee colony is to find a genetic correlation with HB. To that end, University
of British Columbia entomologists led by Robert Parker examined
protein expression in bees from a variety of hives. They particularly looked at
proteins produced within the antennae of nurse bees. After all, it’s the nurse
bees that handle the larvae, and they presumably use their antennae to
distinguish between the sick and healthy larvae. The researchers also
determined the protein composition within the exoskeletons of larvae, the first
line of attack for mites.

The entomologists did find specific proteins that correlated with high
levels of HB, most notably factors that stimulate antimicrobial activity and
clotting. As more data is collected, beekeepers might be able to use the
information to stave off local extinctions in their hives.Robert Parker, Marta Guarna, Andony Melathopoulos, Kyung-Mee Moon, Rick White, Elizabeth Huxter, Stephen Pernal, & Leonard Foster (2012). Correlation of proteome-wide changes with social immunity behaviors provides insight into resistance to the parasitic mite, Varroa destructor, in the honey bee (Apis mellifera)
Genome Biology DOI: 10.1186/gb-2012-13-9-r81

Stochastic Scientist? What's up with that?

Why the Stochastic Scientist? As I'm sure you all know, 'stochastic' is another word for 'random', which is what I intend for the focus of this blog. Although my formal training is as a molecular biologist, there are many other fields of science that are also fascinating and beautiful. It's my intention to blog about which ever scientific discovery or invention catches my, and hopefully your, fancy.

I also hope to inspire people to learn more about science. By choosing among a huge variety of scientific endeavors, I'll undoubtably hit upon something that will pique my readers' interest.

I guess I could have called my blog 'The Joy of Science', but that wouldn't have been quite so random.